Screw retainer



Patented July 28,1931

UNITED STA urns 3. many, or wrxs'r Bron-mm), onro SCREW RETAINER Application filed November 16, 1929. Serial No. 407,634.

This invention relates to a retainer or locking devicefor screws and is herein shown and described in connection with a set-screw although not necessarily limited thereto as will be apparent to those skilled in the art. The objects of the invention are the provision of a very simple and inexpensive device capable of being applied to ordinary slotted screws to prevent their acci- '10 dental loosening.

In the drawings accompanyin and forming a part of this application I ave shown an illustrative embodiment of my improvements. Figs. 1 and 2 are sectional views.

at right angles to each other of a shaft and pulley held together by a set-screw and containing my improvements; Fig. 3 is a sectional view similar to Fig. 1 showing the mode of applying my improved set-screw retainer; Fig. 4 is perspective view of the retainer applied to the set-screw in its operative relation, a part of the set-screw being broken away; Fig. 5 is a longitudinal sectional view through one of the retainers by itself; Fi 6 is a perspective view of the retainer; ig. 7 is a perspective view of a slight modification; Figs. 8 and 9 show alternative modes of starting the cross bar; and Figs. 10 and 11 are, respectively, a sectional view arid a perspective view of a modification. 1

My improved screw-retainer comprises a helical metal element which may be either of wire or of sheet metal, preferably of somewhat springy or resilient nature although almost any common steel wire or strip metal will serve without special attention being paid to composition or temper. The wire or strip is formed so as to correspond to the direction of twist.

In Figs. 1 to 9 inclusive I have shown the device as made of wire twisted into the form of a helix. The wire at one end of the coil is bent, first in a direction parallel to the axis of the helix as shown at 2, and then diametrically across the axis of the helix as shown at 3 so as to rest in the bottom of the slot 4 with which the set-screw 5 is provided. The diameter of the wire is such that there is still room in the slot 4. for the screw and retainer.

blade 6 of a screw-driver after is in place. -In Figs; 2, 5, and 6 Ihave.

res PATENT OFFICE this retainer formed with to and symmetrically located with respect to the bend 2, the better to guide the device during its application. opposite end of the wire is cut s own at 8 audit is desirable necessary, that there should be at this point. The outside dia into the threads.

In Figs. 10 and 11 I have tainer made of sheet- In Fig. 7 this is omitted. The

ofi' square as though not a slight burr meter of the .helix issuch that the wire coil fits snugly shown a reor strip-metal, having a circular side-wall 10 and a diametral barportion 11 terior of the threads 12 integral therewit circular portion is and the end of th h. The exformed with e part 10 is spacedfrom the bar 11 to define a slot 13 which may subtend anywhere 1 to about 180. vention the bar 11 from about .In this form of the innot only fills the slot of the screw but projects above it and a slotted tool (not shown) is employed This devi trifle oversize so that to introduce it into the socket.

to turn the ce is made a it ,has to be contracted It is essential when my improved screw retainer is used that tainer be both received within the screw and the rethe threaded aperture or socket; that is to say the slotted end of the screw is turned below the level of the end of the receiving threads. In prac tice the screw is first caused to enter the receiving thread until its slotted end is about level therewith as which the retainer is inserted a driver (or other tool) applied shown in Fig. 3, after nd the screw so as to ad- Vance the screw and retainer together to the bottom of the hole as shown in Figs. 1 and 2. When this retainer fits tightly in the threads as it should, the advancing movement of the screw is not noticeably impeded since the twisting of the helix contracts its diameter so that its turns follow smoothly along the receiving threads, is impeded by the fact that the wire or strip, aided by the of the burr with the threads but unscrewing the friction of engagement (when. such tilt! 2 A a 1,a1e,ue1

burr exists) causes the entire helix to extool-engaging proyisions, and a threaded p'and in size and lock itself ever more tight- ;socket m which sald screw is introduced to 1y a ainst the socket. Indeed when a device a polnt below the top of the socket, of an of t e proper size is employed it'is always expanslve metal member screwed into the I I diflicult and sometimes impossible to remove same threads outside of said screw and inthe screw until the wire retainer is first terlocked with said tool-engaging prov1- forcibly pried out of the. hole. sions. a

I do not limit myself to the use of any 7. The combination of a'screw h aV1ng a fixednumber of turns of the thread; I preslot and a threaded socket m which said fer to use from one to four turns since this screw is seated, of an expansive metal mem- '5 number affords easy asembling without takber screwed into said socket outside of said I ing up undue s ace, butless or more can screw and having a part engagmg sa1d slot. 7 be employed. T e device is perfectly oper- 8; The combination of a screw having a ative with a smaller number of turns alslot of an expansive frictlon member havthough it becomes somewhat more diflicult ing a part adapted to enter said slot and a to install properly, and it is equally operaspiral ortion ada ted to be turned into the tive with a larger number of turns, the only same t reads as t e scre'w. disadvantage being that it may necessitate In testimony whereof I hereunto afiix my using either an uncomfortabl short screw-1 slgnature. driver or an uncomfortably eep socket. When made of wire the portion 2 of the device is preferably displaced slightly inwardly from the cylindrical surface defined by the exterior of the helix, either by being 1 a5 bent abruptly inwardly as shown at 2 in a0 15%. 5 and 9 or more slowly as shown at 2" in igs. 1 and 8. It will be understood that other slight changes can be made within the scope of my invention and I do not limit so myself in any wise except as s ifically set as forth in my several claims w 'ch I desire may be construed broadly each independently of limitations contained in other claims. Having thus described myinvention what JAMES B. KIBBY.

86 I claim 15: 1 100 v 1. A screw-retainer consisting of a wire helix screwed into the socket above thev screw and having a part located in the screw .slot.. 7

2. A screw-retainer consisting of an ex- 1 105 ansive and collapsible metal member havmg threads adapted to fit tightl the same threads which the screw fits an having a cross-piece projecting beyond said threads af pne end and adapted to fit in the screw- 110 3. A device for locking a screw in a threaded opening characterized by the de- V166 following and locking itself into the to same threads which receive the screw.

4. A device for lockin a set-screw'consisting of an expansible e ement adapted to follow the' screw into the same threads which the screw itself occupies, and by expansion to grip said threads frictionally and oppose the unscrewing of said screw.

5. A device for looking a screw in .a threaded hole consisting of a part which fits the end of the screw and is rotated along with the screw, and a second expansible art 1 5 integral therewith which enters the ole after the screw and frictionally grips the same threads which the screw passed in its entrance.

5- 6; The combination of a screw having 

